CHEYENNE, Wyo. (AP) - State livestock officials are encouraging ranchers to keep their cattle away from elk to avoid getting brucellosis, a bacterial disease that can cause cows to abort their calves.

But abundant elk might make separation difficult in parts of northwest Wyoming where the disease keeps reappearing in cattle, State Veterinarian Jim Logan said.

Wyoming went four years without a case of brucellosis in cattle until laboratory tests confirmed the disease in a cow in Park County in November. Test results on a second suspected case in Sublette County are pending and should come back later this week or early next week, Logan said.

Analysis is underway at the Wyoming State Veterinary Laboratory in Laramie and the federal National Veterinary Services Laboratory in Ames, Iowa.

“We’re waiting on tissue culture and that just takes time,” Logan said Tuesday. “There’s nothing you can do to hurry it up. Just give it time to grow.”

The other cattle in the Park County herd have tested negative, and test results are pending for the others in the Sublette County herd. Livestock officials have quarantined both herds and five others - one in Park County and four in Sublette County - that came in contact with the two herds.

People can get brucellosis by drinking unpasteurized milk, but human cases are rare in the U.S.

A major outbreak in cattle could impede Wyoming ranchers’ ability to do business outside the state, causing major economic damage.

Yellowstone National Park has gone so far as to slaughter thousands of bison, which also can carry brucellosis, to keep them away from cattle in Montana in winter. Montana, unlike Wyoming, hasn’t had brucellosis in cattle recently. Cattle in Wyoming typically catch brucellosis from elk.

Ranchers can put up fences to separate their cattle from elk or make sure cattle don’t graze areas where infected elk have recently given birth, Wyoming Stock Growers Association Executive Vice President Jim Magagna said Wednesday.

“As long as we have it in the wildlife, these occasional transfers - in spite of a lot of good efforts both by the game and fish managers and by the ranchers - they’re just somewhat inevitable,” said Magagna.

The good news - if there is any with brucellosis - is testing apparently caught the cattle brucellosis cases early. That shows Wyoming’s testing program works, Magagna said.

The Wyoming Stock Growers Association supports ongoing research into developing more effective brucellosis vaccines for both cattle and wildlife, he said.